摘要目的:评估儿童患者利用笔形线束扫描（PBS）技术，进行部分椎体照射的全脑全脊髓质子放疗（VBSpCSI）的急性不良反应及相关影响因素，以及脊柱生长情况和生存结果。方法:回顾性分析2020年1月至2022年12月，在河北一洲肿瘤医院接受基于PBS技术VBSpCSI治疗的70例患儿的病历资料，并继续随访至2023年11月。评估患儿的急性不良反应，并采用线性回归分析和受试者操作特征曲线探索椎体剂量与不良反应的关系。通过随访MRI测量患儿脊柱Cobb角，评估放疗后脊柱生长状况。应用Kaplan-Meier方法统计患儿的总生存（OS）和无进展生存（PFS）情况。结果:患儿放疗时的中位年龄为6岁（范围2~16岁）。2名患儿（3%）发生≥3级胃肠道不良反应，7名患儿（10%）出现1级放射性食管炎。放疗期间患儿白细胞计数、中性粒细胞绝对值和淋巴细胞绝对值的最低值分别与椎体V 5 Gy（ P=0.009、0.006、0.001）、椎体V 20 Gy（ P=0.007、0.011、<0.001）呈显著负相关。当椎体V 5 Gy<86.5%、椎体V 20 Gy<73.2%时，≥3级骨髓抑制的发生率显著减少（ P<0.001、=0.001）。患儿月龄较小及接受化疗也与急性血液学不良反应加重显著相关。43名具有MRI影像随访的患儿中，无患儿出现脊柱侧弯、后凸或慢性腰背疼痛。患儿3年OS、PFS率分别为95.7%、86.4%。 结论:对儿童患者使用PBS技术进行VBSpCSI，结果显示急性不良反应可控，椎体V 5 Gy、V 20 Gy与血液学不良反应呈现剂量-效应关系，非血液学不良反应的发生率较低。患儿的脊柱生长和生存情况短期内未见不良影响。

abstractsObjective:To evaluate the acute toxicities and related influencing factors of vertebral-body-sparing proton craniospinal irradiation (VBSpCSI) using pencil beam scanning (PBS) technology in pediatric patients, and to assess spinal growth and survival outcomes.Methods:A retrospective analysis was conducted on 70 pediatric patients treated with PBS-based VBSpCSI at Hebei Yizhou Cancer Hospital between January 2020 and December 2022, and continued to follow up until November 2023. Acute toxicities were assessed, and linear regression analysis combined with receiver operating characteristic curve were employed to investigate the dose-effect relationship between vertebral dose and toxicities. Spinal growth after radiotherapy was evaluated by measuring the Cobb angle on follow-up MRI. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method.Results:The median age of patients at the time of irradiation was 6 years (range, 2-16 years). Two patients (3%) developed grade ≥3 gastrointestinal toxicities, while 7 patients (10%) experienced grade 1 radiation-induced esophagitis. The nadirs of white blood cell count (WBC), absolute neutrophil count (ANC), and absolute lymphocyte count (ALC) during treatment were significantly negatively correlated with vertebral V 5 Gy ( P=0.009, 0.006, 0.001) and vertebral V 20 Gy ( P=0.007, 0.011, <0.001). When vertebral V 5 Gy<86.5% and vertebral V 20 Gy<73.2%, the incidence of grade ≥3 myelosuppression was significantly reduced ( P<0.001, =0.001). Additionally, younger patient age (in months) and concurrent chemotherapy were also significantly associated with increased acute hematologic toxicity. Among 43 patients with MRI follow-up, no scoliosis, kyphosis, or chronic lumbosacral pain was observed. The 3-year OS and PFS rates were 95.7% and 86.4%, respectively. Conclusions:PBS-based VBSpCSI in pediatric patients demonstrates manageable acute toxicities, with a clear dose-effect relationship between vertebral V 5 Gy , V 20 Gy and hematologic toxicities, and the incidence of non-hematological toxicities remains low. No adverse effects on spinal growth or survival outcomes were observed in the short term.